Association of inferior vena cava diameter, functional disability, and dehydration with clinical outcomes in elderly...

Dehydration is a common yet frequently underestimated condition in elderly patients and is associated with increased mortality and intensive care unit (ICU) admission. Clinical assessment of volume status remains challenging in this population. This study aimed to evaluate the relationship between inferior vena cava (IVC) diameter, functional disability, dehydration, and clinical outcomes in elderly emergency department (ED) patients.

This prospective observational study enrolled patients aged ≥ 60 years presenting to a tertiary ED with non-traumatic conditions between April 2023 and December 2024. IVC diameter was measured ultrasonographically at baseline (IVC₁) and post-resuscitation (IVC₂). Functional status was assessed using the modified Rankin Scale (mRS). Primary outcomes were ICU admission and in-hospital mortality.

Among 212 elderly patients, 69.3% had a fluid deficit. Overall, 57.5% were hospitalized, 43.8% required ICU care, and in-hospital mortality occurred in 21.7%. Patients with fluid deficit demonstrated significantly lower IVC₁ diameter (10.5 ± 2.9 vs. 17.2 ± 2.2 mm, p < 0.001). Non-survivors exhibited lower IVC₁ (p = 0.038) and higher percentage IVC change (Δ%IVC) (p < 0.001). Functional disability correlated with lower IVC₁ (p < 0.001) and increased fluid deficit (p = 0.004). Multivariate analysis identified lower GCS (OR 0.37, 95% CI 0.25-0.55) and higher Δ%IVC (OR 1.10, 95% CI 1.04-1.16) as independent predictors of mortality (both p < 0.001).

Dehydration is prevalent among elderly ED patients and strongly associated with adverse outcomes. Point-of-care IVC ultrasonography combined with functional assessment enables rapid identification of high-risk patients. Lower IVC₁ diameter, higher Δ%IVC, and greater functional impairment predict ICU admission and mortality, supporting their integration into routine geriatric emergency care.